399401 has 2 divisors, whose sum is σ = 399402. Its totient is φ = 399400.

The previous prime is 399391. The next prime is 399403. The reversal of 399401 is 104993.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 336400 + 63001 = 580^2 + 251^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399401 is a prime.

Together with 399403, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 9.

It is not a weakly prime, because it can be changed into another prime (399403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199700 + 199701.

It is an arithmetic number, because the mean of its divisors is an integer number (199701).

2³⁹⁹⁴⁰¹ is an apocalyptic number.

It is an amenable number.

399401 is a deficient number, since it is larger than the sum of its proper divisors (1).

399401 is an equidigital number, since it uses as much as digits as its factorization.

399401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 399401 is about 631.9818035355. The cubic root of 399401 is about 73.6438326842.

The spelling of 399401 in words is "three hundred ninety-nine thousand, four hundred one".